Recently, liquid crystal displays (LCD) have been widely applied in electrical products due to the rapid progress of optical technology and semiconductor technology. Moreover, with advantages of high image quality, compact size, light weight, low driving voltage and low power consumption, LCDs have been introduced into portable computers, personal digital assistants and color televisions, and have become the mainstream display apparatus.
FIG. 1 shows a diagram of part of a conventional source driver 100 of the LCD. The source driver 100 includes a plurality of channels. The data stored in buffers (BUF_HV, BUF_LV) of channels is inputted to a multiplexer (MUX) 102 and further sent to a display 104 via output pads (114, 116) to show corresponding images on the display 104. A transistor 106 is electrically connected between the outputs of the source driver to share the voltages on the outputs if needed.
However, when the power supply powering the source driver is being turned off, the power supplying to the source driver decreases and the buffers may malfunction owing to the power insufficient, which results in abnormal images, such as line defects or band mura, shown on the display.